Assessment of Multiple Anaerobic Co-Digestions and Related Microbial Community of Molasses with Rice-Alcohol Wastewater

Sohail Khan, Fuzhi Lu, Qiong Jiang, Chengjian Jiang, Muhammad Kashif and Peihong Shen
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Sohail Khan: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning 530005, China
Fuzhi Lu: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning 530005, China
Qiong Jiang: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning 530005, China
Chengjian Jiang: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning 530005, China
Muhammad Kashif: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning 530005, China
Peihong Shen: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning 530005, China

Energies, 2020, vol. 13, issue 18, 1-16

Abstract: Molasses is a highly dense and refined byproduct produced in the sugarcane industry, and it contains high amounts of degradable compounds. Through bioconversion, these compounds can be transformed into renewable products. However, the involved biological process is negatively influenced by the high chemical oxygen demand (COD) of molasses and ion concentration. The co-digestion of molasses with rice-alcohol wastewater (RAW) was compared with its mono-digestion at an increasing organic loading rate (OLR). Both processes were assessed by detecting the COD removal rate, the methane contents of biogas, and the structure and composition of microbial communities at different stages. Results showed that the co-digestion is stable up to a maximum OLR of 16 g COD L −1 d −1 , whereas after the acclimatization phase, the mono-digestion process was disturbed two times, which occurred at a maximum OLR of 9 and 10 g COD L −1 d −1 . The volatile fatty acids (VFAs) observed were 2059.66 mg/L and 1896.9 mg/L, which in mono-digestion causes the inhibition at maximum OLRs. In the co-digestion process, the concomitant COD removal rates and methane content recorded was 90.72 ± 0.63% 64.47% ± 0.59% correspondingly. While in the mono-digestion process, high COD removal rate and methane contents observed were 89.29 ± 0.094% and 61.37 ± 1.06% respectively. From the analysis of microbial communities, it has been observed that both the bacterial and archaeal communities respond differently at unlike stages. However, in both processes, Propionibacteriaceae was the most abundant family in the bacterial communities, whereas Methanosaetaceae was abundant in the archaeal communities. From the current study, it has been concluded that that rice-alcohol wastewater could be a good co-substrate for the anaerobic digestion of molasses in terms of COD removal rate and methane contents production, that could integrate molasses into progressive biogas production with high OLR.

Keywords: molasses; rice-alcohol wastewater; co-digestion; mono-digestion; microbial community (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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